The present invention relates generally to a machine tool collet. In particular to a collet for holding lathe stock in alignment on a lathe machine.
During machining, the work stock has a tendency to move with respect to the longitudinal axis of the stock. This movement is both circular and axial and is determined by the cut being made. Another factor involved, is that long bar or rod stock is often used as the work stock. The bar or rod is fed through the collet so as to enable the lathe to work on different areas of the work stock.
There have been a variety of collets made for this purpose however they have inherent weaknesses. If the collets were made to grip the work stock with the force necessary to keep the stock from moving, the collet would not release the work stock fast enough to permit proper feed out. The collets would also have a tendency to stick to the stock and not release. If the collets were made to release fast, there would be insufficient grip to immobilize the work stock. Additionally, the collets would have short life times as they would wear out. In order to increase the useful life of collets they are hardened. However, in some cases, this causes them to be brittle and fracture prematurely.